The invention relates to a set of tools for a reception station in a press for shaping sheets of paper or cardboard, comprising a moving slide and a number of bars constituting a grid for non-stop reception of blanks, the set of tools comprising a bottom blank-separating tool.
The invention also relates to a reception station on a press for shaping sheets of paper or cardboard, comprising a moving slide adapted to receive a number of bars for forming a grid for non-stop reception of blanks.
For each run, presses shaping sheets of paper, solid fibre board or corrugated cardboard use a set of shaping tools specific for a particular job. The typical set of tools comprises:
a make-ready sheet,
a member for cutting,
a top waste ejection tool,
a bottom ejection board,
a top blank-separating tool and
a bottom blank-separating tool.
The bottom blank-separating tool can comprise a general-purpose frame adapted to receive adjustable cross-members or an internal grid made to measure and defining meshes substantially corresponding in shape to the blanks. The bottom blank-separating tool can likewise comprise a plate in which a number of openings are cut by a laser or water jet, the periphery of the openings corresponding to that of the blanks for separating. The openings in the bottom blank-separating tool are usually in a number of transverse rows disposed either exactly one behind the other with a transverse shift.
The terms xe2x80x9ctransversexe2x80x9d and xe2x80x9clongitudinalxe2x80x9d here are used with reference to the direction of advance of the sheets in the shaping press.
In order to form stable stacks of separated blanks under the tool on the reception pallet of the reception station, it is periodically necessary to insert a stabilising sheet. In order to insert the sheet without stopping the production unit, a device commonly called a xe2x80x9cnon-stop gridxe2x80x9d is used. The device comprises a slide movable in the longitudinal direction of the press. The slide has two transverse beams on which bars can be disposed for forming a grid for non-stop reception of blanks. The bars generally have a rod-like shape. The head of the rod can engage in a recess in the beam furthest from the reception station and can be screwed therein. The rod, over a zone near the head thereof, rests on a second transverse beam of the slide, and near its other end the rod rests on a transverse roller in the immediate neighbourhood of the blank reception zone. For the purpose of insertion, the slide moves under the bottom blank-separating tool and a pair of bars holds each blank as it falls. In the case of large-area blanks, the number of bars per blank may be greater. At each instant, the non-stop grid receives the blanks, which form a stack during the insertion operations. A pre-selector defines the number of blanks per packet and/or the height of the stacks. The entire device operates automatically in known manner in accordance with a pre-programmed cycle.
The said set of tools must be very accurately positioned in the various stations of the press at the beginning of each job. In the case of short repeated runs in particular, the productivity of the unit is closely dependent on the speed of positioning and adjustment of the tools.
In order to change rapidly from one job to another, the waste ejection tools and the top blank-separating tool are often mounted and position-marked outside the machine, on an adjustment table specially designed for this purpose. They can therefore be prepared while the machine is working on the previous job and do not slow down overall production during adjustment. On the other hand the bars forming the grid for non-stop reception of blanks must be mounted on the moving slide during a stoppage of the machine between two jobs. In known shaping presses, the operator must place each bar on the moving slide, visually align the bottom blank-separating tool disposed in the station, and transversely move the bars so as to place two or three bars in vertical alignment with each opening in the bottom blank-separating tool. The alignment is made slotwise, in an uncomfortable position for the operator. Adjustment of the position of all the bars is the most laborious operation required between jobs. If done badly, the stacks of blanks formed at the reception station will not be straight.
A first object of the invention is greatly to speed up the operation of positioning the bars constituting the grid for non-stop reception of blanks. A second object of the invention is to make the positioning more reliable and independent of the alignment capacity of the operator. A third object is to clamp and unclamp the bars quickly on the moving slide.
These objects are achieved by a set of tools comprising a master tool coupled with the bottom separating tool and comprising two boards adjustable on two transverse beams of the moving slide and with upper edges having the same profile, the said upper edge profile comprising a number of serrated recesses in shape matching the cross-section of the bars, the recesses being adjusted to correspond to the transverse positions of the openings in the bottom separating tool.
This object is also achieved by a reception station of the kind defined in the preamble, in that the moving slide comprises means for holding, retaining and centring the said master tool.
According to the invention the two boards forming the master tool are disposed on and/or against the two transverse beams of the slide. The centring means positions them transversely relative to the bottom blank-separating tool without the operator needing to make further adjustments. A bar is positioned very easily by placing the rod part in two recesses in the facing boards, thus efficiently guiding the rod and positioning it opposite the corresponding opening in the bottom blank-separating tool when the slide advances for the purpose of insertion.
The head of each bar rests against the slide beam furthest from the reception zone and can be individually screwed. Preferably the slide comprises clamping means for simultaneously fixing and clamping all the bars once adjusted on the slide by means of the master tool. The clamping means can comprise a horizontal transverse beam movable between a first position where it does not impede positioning the bars on the slide and a second position where it abuts the heads of the bars adjusted on the slide, and can also comprise a locking device for locking the moving beam in the said second position.